Lowdin population analysis
Clicked A Few Times
3:32:27 PM PDT - Fri, Oct 7th 2011
Hi,
  According to the manual, constrained DFT uses Lowdin populations by default (Mulliken not recommended). I would like to set up a calculation by taking converged MOs as a guess, then running CDFT with a cluster of atomic charges constrained to the value in the original calculation (just as a check, to ensure the same or similar wavefunction is produced). To do this, I guess I'd need the Lowdin charges for the original WF. Is there a database key/value pair that can be set to produce Lowdin population analysis, and if so what is it?

Thanks.

Forum Vet
11:03:07 AM PDT - Mon, Oct 10th 2011
Chris,

How counter intuitive it may sound, but adding the keyword "mulliken" to the dft block should print out both the Mulliken and Lowdin charges.

Bert


Quote:Cchang Oct 7th 10:32 pm
Hi,
  According to the manual, constrained DFT uses Lowdin populations by default (Mulliken not recommended). I would like to set up a calculation by taking converged MOs as a guess, then running CDFT with a cluster of atomic charges constrained to the value in the original calculation (just as a check, to ensure the same or similar wavefunction is produced). To do this, I guess I'd need the Lowdin charges for the original WF. Is there a database key/value pair that can be set to produce Lowdin population analysis, and if so what is it?

Thanks.

Clicked A Few Times
1:03:09 PM PDT - Mon, Oct 10th 2011
Thanks Bert!
  Cheers,  Chris

Clicked A Few Times
1:59:20 PM PST - Fri, Dec 23rd 2011
Not seeing Lowdin charges
Bert,

I tried adding "mulliken" in both a separate properties section, and in the dft block as you suggested; however, I'm not seeing anything labeled as "Lowdin" or anything else that would suggest an alternative charge model. What should I be looking for? NWChem 6.0 on Hopper @ NERSC.

Thanks,

Chris

Forum Regular
4:21:29 PM PST - Tue, Dec 27th 2011
Hi Chris,

Try the following:

dft
 mulliken

 ...
end
task dft

this will print out Mulliken and Lowdin sections in the output. Let me know if it doesn't work.

Best,
-Niri

Clicked A Few Times
12:05:09 PM PST - Tue, Jan 3rd 2012
Hi Niri,
What keyword would be good to search on to find the Lowdin section? With the MO output, the log files are quite long.

Clicked A Few Times
9:55:02 AM PST - Wed, Jan 4th 2012
Niri--Never mind, the analysis output contained the Lowdin data this time, and the log file was much shorter than it has been. Curious.

Just Got Here
3:30:12 AM PDT - Thu, Aug 30th 2012
Quote:Cchang Jan 4th 9:55 am
Niri--Never mind, the analysis output contained the Lowdin data this time, and the log file was much shorter than it has been. Curious.


Dear NWCHEM users,
I did the Lowdin and Mulliken population analysis to get partial charges for QM atoms in a QMMM simulation. But, results seems strange to me because, for example, for an O atom it results in 8.43 while the ESP analysis results in -0.64 (that looks reasonable). Is there any one who can help me to extract the real partial charges out of these numbers?

Best,
Hassan.

Clicked A Few Times
8:45:36 PM PDT - Sun, Oct 14th 2012
Quote:Niri Dec 27th 4:21 pm
Hi Chris,

Try the following:

dft
 mulliken

 ...
end
task dft

this will print out Mulliken and Lowdin sections in the output. Let me know if it doesn't work.

Best,
-Niri


Thanks for the post. I did this along with / separately

dft
cdft 1 x charge 0.0 pop lowdin
....
end
task dft

but had no luck in getting the Lowdin charges with NWCHEM 6.1 @ hopper.nersc

Can some one please enlighten me with the proper keyword? Thanks in advance.

Forum Vet
12:55:13 PM PDT - Mon, Oct 15th 2012
Himadride,
The input below is an example for how to calculate the Lowdin population analysis.

start n4
geometry
N -0.08327803 -0.57614137 -0.00048040
N 0.17646529 -1.65378010 0.00040716
N 0.44621621 1.56364198 0.00224466
N -0.53940347 0.66627949 -0.00217143
end
basis
* library 6-31g*
end
dft
odft
xc b3lyp
mult 3
cdft 1 2 charge 1.0
cdft 3 4 charge -1.0
mulliken
end

task dft

Clicked A Few Times
1:16:59 PM PDT - Mon, Oct 15th 2012
Thanks for the reply. But it still does not work. Is there any other work around ? Thanks in advance.

Forum Vet
2:56:30 PM PDT - Mon, Oct 15th 2012
I have just tried it with both the 6.1 and 6.1.1 default binaries on hopper and it works for me.

apra/cdft> egrep wdin cdft.out.2325240.sdb 
    Total Density - Lowdin Population Analysis

     Spin Density - Lowdin Population Analysis

Quote:Himadride Oct 15th 12:16 pm
Thanks for the reply. But it still does not work. Is there any other work around ? Thanks in advance.

Clicked A Few Times
12:11:36 AM PDT - Thu, Oct 18th 2012
Thank you for the reply. It definitely works with the closed shell systems. My system is open shell and I use RODFT module accompanied by cgmin solver. Can you please let me know about it, whether with RODFT open shell systems too similar keywords are valid? Thanks in advance.

Forum Vet
1:16:41 AM PDT - Thu, Oct 18th 2012
This is a feature that has not been implemented in the RODFT yet. This will be made available in our next release.

Bert

Quote:Himadride Oct 18th 7:11 am
Thank you for the reply. It definitely works with the closed shell systems. My system is open shell and I use RODFT module accompanied by cgmin solver. Can you please let me know about it, whether with RODFT open shell systems too similar keywords are valid? Thanks in advance.


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